Nanoclusters are an important class of materials that are having a major impact in a diverse range of applications, including chem- and biodetection, catalysis, optics, and data storage. The use of such particles dates back to the middle ages, and the scientific study of them has spanned over a century. These nanostructures are typically made from molecular precursors, and there are now a wide variety of compositions, sizes, and even shapes available. Because of their unusual and potentially useful optical properties, nanoprism structures in particular have been a recent synthetic target of many research groups. We recently reported a high yield photosynthetic method for the preparation of triangular nanoprisms from silver nanospheres. For many nanoparticle syntheses, an Ostwald ripening mechanism, where large clusters grow at the expense of smaller ones, is used to describe and model the growth processes. This type of ripening typically results in unimodal particle growth. Thus, method of controlling the growth and ultimate dimensions of such structures is desired. Such a method will necessarily fall outside of the known Ostwald ripening mechanisms.